Effects of microorganisms on hydraulic conductivity decrease in infiltration (original) (raw)
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Abstract
Microorganisms can clog pores in soils and decrease hydraulic conductivity and infiltration. We did three column experiments to clarify the effects. In all three columns, glucose solution of 50 μg cm‑3 was percolated for 120 days, and both the saturated hydraulic conductivity, Ks, and the volume ratio of the gas phase, a, were measured continuously. The Ks decreased rapidly for the initial 10 days, and it slowly decreased for the following 110 days. By adding chloramphenicol to the second column as bactericide and cycloheximide to the third column as fungicide, we observed clogging by bacteria and fungi, respectively, bacterial clogging proceeding more rapidly than the fungal clogging. The volume of the gas phase increased and reached the maximum value of 30.6% after 103 days from the beginning of percolation. This large amount of gas was retained in the soil pores as bubbles and occluded the pathways of water, resulting in the decrease in Ks. When the percolating solution was changed to sodium azide (a strong biocide), after 120 days the volume of the gas phase decreased rapidly, and Ks increased simultaneously.
Publication:
European Journal of Soil Science
Pub Date:
June 1998
DOI:
10.1046/j.1365-2389.1998.00152.x
Bibcode: